Nutrition and health

Objectives:
Does consumption of fruits and vegetables reduce risk of endometrial cancer?

Study design:
This review article included  of 21 case-control studies and 6 cohort studies.

Results and conclusions:
The investigators found that vegetables consumption significantly reduced risk of endometrial cancer with 24% [pooled odds ratio [OR], relative risk [RR], hazard ratio [HR] = 0.76, 95% CI = 0.63 to 0.91].

The investigators found that cruciferous vegetables consumption significantly reduced risk of endometrial cancer with 19% [pooled OR = 0.81, 95% CI = 0.70 to 0.94].

The investigators found that dark green and yellow/orange combined vegetables consumption significantly reduced risk of endometrial cancer with 36% [pooled OR = 0.64, 95% CI = 0.42 to 0.97].

The investigators found that fruits consumption significantly reduced risk of endometrial cancer with 19% [pooled OR = 0.81, 95% CI = 0.70 to 0.92].

The investigators found these results were primarily based on studies of high quality and exhibited either by case-control only or a combination of case-control and cohort studies. Additionally, the results varied by geographic location, such as Western areas, the US and Italy.

The investigators concluded that consumption of fruits and vegetables has beneficial effects on endometrial cancer risk and that specific kinds of fruits and vegetables should be recommended differently due to their outstanding bioactive components.

Original title:
The influence of dietary vegetables and fruits on endometrial cancer risk: a meta-analysis of observational studies by Lu YT, Gunathilake M and Kim J.

Link:
https://pubmed.ncbi.nlm.nih.gov/36151331/

Additional information of El Mondo:
Find more information/studies on cancer and fruit and vegetable consumption right here.

Objectives:
There is keen interest in better understanding the impacts of alpha-linolenic acid (ALA), a plant-derived n-3 fatty acid, in ameliorating the development of cancer. However, results of several prospective cohort studies present an inconsistent association between ALA intake and the incident colorectal cancer (CRC). Therefore, this review article has been conducted.

Does a high dietary intake of alpha-linolenic acid or a high level of alpha-linolenic acid in blood reduce risk of colorectal cancer (colon and rectal cancer)?

Study design:
This review article included 15 cohort studies (11 studies on diet and 5 studies on biomarkers including 4 on blood and 1 on adipose tissue) with 12,239 colorectal cancer cases occurred among 861,725 participants.
The mean follow-up was 9.3 years (ranging from 1 to 28 years).
Among all of the included studies, quality scores assessed by the 9-star NOS ranged from 7 to 9, with a median quality (≤7 stars) in 2 studies and high quality (≥ 8 stars) in 13 studies.

There was no publication bias.

Results and conclusions:
The investigators found higher level of alpha-linolenic acid in blood significantly reduced risk of colorectal cancer with 17% [summary RR = 0.83, 95% CI = 0.69 to 0.99, I2 = 0.0%].

The investigators found each 0.1% increase in the level of alpha-linolenic acid in blood was significantly associated with a 10% reduction in colorectal cancer risk [summary RR = 0.90, 95% CI = 0.80 to 0.99, I2 = 38.6%].

The investigators no significant dose-response association between dietary intake of alpha-linolenic acid and the incident colorectal cancer [p for non-linearity = 0.18; p for linearity = 0.24].

The investigators concluded that higher blood levels of alpha-linolenic acid reduce risk of colorectal cancer while higher dietary intake of alpha-linolenic acid does not reduce risk of colorectal cancer. Encouraging the consumption of foods rich in alpha-linolenic acid to improve its levels in the blood may potentially decrease the risk of colorectal cancer. Nevertheless, well-designed and large-scale cohort studies with biomarkers are still needed for better reconfirming the potential impacts of alpha-linolenic acid intake in the primary prevention of colorectal cancer.

Original title:
Association of Dietary Intake and Biomarker of α-Linolenic Acid With Incident Colorectal Cancer: A Dose-Response Meta-Analysis of Prospective Cohort Studies by Dai ZB, Ren XL, […], Xu L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9301188/

Additional information of El Mondo:
Find more information/studies on colorectal cancer and alpha-linolenic acid consumption right here.

Objectives:
Colorectal cancer is one of the most commonly diagnosed and deadly cancers worldwide. Epidemiological studies on the relationship between folate intake and the risk of colorectal cancer have reported inconsistent findings since folate fortification in the USA. Therefore, this review article has been conducted.

Does a high folate (folic acid) ietary intake reduce risk of colorectal cancer (colon and rectal cancer)?

Study design:
This review article included 24 cohort studies involving 6,165,894 individuals, of which 37,280 persons with colorectal cancer.

Results and conclusions:
The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 12% [combined relative risk (RR) = 0.88, 95% CI = 0.83 to 0.92, p = 0.0004].
Significantly means that there is an association with a 95% confidence.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 3% among persons witih medium alcohol consumption [RR = 0.97, 95% CI = 0.96 to 0.99, p = 0.008].
Significantly because RR of 1 was not found in the 95% CI of 0.96 to 0.99. RR of 1 means no risk/association.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 5% among persons witih high alcohol consumption [RR = 0.95, 95% CI = 0.92 to 0.97, p = 0.003].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake did not reduce risk of colorectal cancer among non-drinkers [RR = 1.00, 95% CI = 0.98 to 1.02, p = 0.827].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colon cancer with 14% [RR = 0.86, 95% CI = 0.81 to 0.92, p = 0.0004].
Significantly because the calculated p-value of 0.0004 was less than the p-value of 0.05.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake did not reduce risk of rectal cancer [RR = 0.92, 95% CI = 0.84 to 1.02, p = 0.112].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer in USA and Europe but not in other regions.

The investigators concluded that high folate dietary intake reduces risk of colon cancer, particularly in people with medium or high alcohol consumption, but it still needs to be further confirmed.

Original title:
Folate intake and risk of colorectal cancer: a systematic review and up-to-date meta-analysis of prospective studies by Fu H, He J, […], Chang H.

Link:
https://pubmed.ncbi.nlm.nih.gov/35579178/

Additional information of El Mondo:
Find more information/studies on colorectal cancer and folic acid consumption right here.

Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start.

Objectives:
The association between meat intake and hepatocellular carcinoma (HCC) risk is still unclear. Therefore, this review article has been conducted.

Does a higher dietary intake of meat increases the risk of hepatocellular carcinoma?

Study design:
This review article included 17 observational studies involving 2,915,680 participants, of which 4,953 cases of hepatocellular carcinoma.

10 studies reported red meat intake, 9 reported white meat intake, 9 reported fish intake, 7 reported processed meat intake and 5 reported total meat intake.

Results and conclusions:
The investigators found results showed that the consumption of red meat [relative risk = 1.04, 95% CI = 0.91 to 1.18, I2 = 50.50%, p = 0.033] and total meat intake [relative risk = 1.01, 95% CI =  0.90 to 1.13, I2 = 15.50%, p = 0.316] were not significantly associated with risk of hepatocellular carcinoma.

The investigators found, however, a higher dietary intake of processed meat significantly increased the risk of hepatocellular carcinoma with 20% [relative risk = 1.20, 95% CI = 1.02 to 1.41, I2 = 26.30%, p = 0.228].
Significant because relative risk of 1 was not found in the 95% CI of 1.02 to 1.41. Relative risk of 1 means no risk/association.

The investigators found, in contrast, a higher dietary intake of white meat significantly decreased the risk of hepatocellular carcinoma with 24% [relative risk = 0.76, 95% CI = 0.63 to 0.92, I2 = 68.30%, p = 0.001].

The investigators found, in contrast, a higher dietary intake of fish significantly decreased the risk of hepatocellular carcinoma with 9% [relative risk = 0.91, 95% CI = 0.86 to 0.96, I2 = 40.90%, p = 0.095].

The investigators concluded that a higher dietary intake of processed meat increases the risk of hepatocellular carcinoma, while a higher dietary intake of both white meat and fish decrease the risk of hepatocellular carcinoma. Therefore, these findings suggest that dietary intervention may be an effective approach to preventing hepatocellular carcinoma. These need to be verified with further well-designed observational studies and experimental clinical research.  

Original title:
Meat Intake and the Risk of Hepatocellular Carcinoma: A Meta-Analysis of Observational Studies by Yu J, Liu Z, […], Chen W.

Link:
https://pubmed.ncbi.nlm.nih.gov/35583453/

Additional information of El Mondo:
Find more information/studies on cancer and meat consumption right here.

Processed meats are meats that have been preserved by smoking or salting, curing or adding chemical preservatives. They include deli meats, bacon and hot dogs.

Objectives:
Evidence associating diet with the incidence of renal cell carcinoma (RCC) is inconclusive. Therefore, this umbrella review article has been conducted.

What is the association between diet and renal cell carcinoma incidence?

Study design:
This umbrella review article included 22 meta-analyses with a total of 502 individual studies and 64 summary hazard ratios (HRs) for renal cell carcinoma incidence: dietary patterns or dietary quality indices (n = 6), foods (n = 13), beverages (n = 4), alcohol (n = 7), macronutrients (n =15) and micronutrients (n =19).

No meta-analyses had high methodological quality.

59% of these 502 individual studies were cohort studies (n = 298), 39% were case-control studies (n = 196) and 2% were pooled studies (n = 8).

Sixty (94%) exposures in the included meta-analyses had more than 1,000 cases or 20,000 participants.

Results and conclusions:
The investigators found no dietary factors showed convincing or highly suggestive evidence of association with renal cell carcinoma incidence in the overall analysis.

The investigators found in the overall analysis that dietary intake of vegetables significantly reduced risk of renal cell carcinoma with 26% [summary HR = 0.74, 95% = 0.63 to 0.86, suggestive evidence].

The investigators found in the overall analysis that dietary intake of vitamin C significantly reduced risk of renal cell carcinoma with 23% [summary HR = 0.77, 95% = 0.66 to 0.90, suggestive evidence].

The investigators found in the overall analysis that moderate drinking significantly reduced risk of renal cell carcinoma with 23% [summary HR = 0.77, 95% = 0.70 to 0.84, convincing evidence] in Europe and North America.

The investigators found in the overall analysis that dietary intake cruciferous vegetables significantly reduced risk of renal cell carcinoma with 22% [summary HR = 0.78, 95% = 0.70 to 0.86, highly suggestive evidence] in North America.

The investigators concluded dietary intake of vegetables and vitamin C could reduce renal cell carcinoma risk. Moderate drinking might be beneficial for Europeans and North Americans and cruciferous vegetables might be beneficial to North Americans, but the results should be interpreted with caution because no meta-analyses had high methodological quality. More researches are needed in the future.

Original title:
The role of diet in renal cell carcinoma incidence: an umbrella review of meta-analyses of observational studies by Liao Z, Fang Z, […], Luo Z.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8812002/

Additional information of El Mondo:
Find more information/studies on cancer, vegetables, vitamin C right here.

An umbrella review article is a scientific article which only includes meta-analyses (also called review articles). The results found in an umbrella review article are more reliable than found in an individual review article.

One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of (prospective) cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Does a high olive oil consumption reduce cancer risk?

Study design:
This review article included 37 case-control studies with 17,369 cases (persons with cancer) and 28,294 controls (persons without cancer) and 8 cohort studies with 12,461 incident cases among 929,771 subjects (participants).

Significant publication bias was detected via Egger’s test in the analysis on overall cancer risk [p 0.001], breast cancer [p = 0.013] and gastrointestinal cancer risk [p = 0.048].

Results and conclusions:
The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 31% lower risk of any cancer [pooled RR = 0.69, 95% CI = 0.62 to 0.77].  
Significantly means that there is an association with a 95% confidence.

The investigators found subgroup analyses showed that the protective effect of high olive oil consumption in terms of cancer risk was also significant in case-control studies [37 study arms, RR = 0.65, 95% CI = 0.57 to 0.74] but not in cohort studies [8 study arms, RR = 0.90, 95% CI = 0.77 to 1.05].
Furthermore, the protective association was also found in a multivariate analysis [32 study arms, RR = 0.72, 95% CI = 0.65 to 0.81], a high study quality analysis [RR = 0.72, 95% CI = 0.64 to 0.81], Mediterranean participants [RR = 0.69, 95% CI = 0.60 to 0.79] and non-Mediterranean participants [RR = 0.49, 95% CI = 0.34 to 0.71].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 33% lower risk of breast cancer [pooled RR = 0.67, 95% CI = 0.52 to 0.86].  
Significantly because RR of 1 was not found in the 95% CI of 0.52 to 0.86. RR of 1 means no risk/association.

The investigators found subgroup analyses showed that the beneficial effect was reproducible in case-control studies [RR = 0.63, 95% CI = 0.45 to 0.87] but not in cohort studies.
Furthermore, high olive oil consumption was linked to a reduced breast cancer risk in Mediterranean [RR = 0.67, 95% CI = 0.49 to 0.92] and non-Mediterranean populations [RR = 0.25, 95% CI = 0.07 to 0.89].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 23% lower risk of gastrointestinal cancer [pooled RR = 0.77, 95% CI = 0.66 to 0.89].  
Subgroup analyses showed an inverse relationship between highest olive oil consumption and risk for esophageal cancer [RR = 0.47, 95%CI = 0.24 to 0.93] and pancreatic cancer [RR = 0.58, 95% CI = 0.35 to 0.97].
Furthermore, significant effects were also found in case-control studies [RR = 0.72, 95% CI = 0.61 to 0.85), studies within the Mediterranean area [RR = 0.77, 95% CI = 0.67 to 0.88], multivariate analyses [RR = 0.76, 95% CI = 0.63 to 0.90] and high quality studies [RR = 0.73, 95% CI = 0.62 to 0.86].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 26% lower risk of upper aerodigestive cancer [pooled RR = 0.74, 95% CI = 0.60 to 0.91].  
Subgroup analyses showed results remained significant for case-control studies [RR = 0.74, 95% CI = 0.60 to 0.91], multivariate analyses [RR = 0.75, 95% CI = 0.66 to 0.86] and studies of high quality [RR = 0.68, 95% CI = 0.52 to 0.89].

The investigators found in pooled analysis of case-control studies that highest olive oil consumption was significantly associated with a 54% lower risk of urinary tract cancer [pooled RR = 0.46, 95% CI = 0.29 to 0.72].  
Subgroup analyses showed results remained significant for studies of high quality [RR = 0.46, 95% CI = 0.32 to 0.66].

The investigators concluded highest versus lowest olive oil consumption is associated with 31% lower cancer risk, especially for breast, overall gastrointestinal, upper aerodigestive and urinary tract cancer. Additional prospective cohort studies on various cancer types, especially in non-Mediterranean regions, as well as large randomized trials, seem desirable in order to provide further insight into the role of olive oil in preventing cancer.

Original title:
Olive oil intake and cancer risk: A systematic review and meta-analysis by Markellos C, Ourailidou ME, […], Psaltopoulout T.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8751986/

Additional information of El Mondo:
Find more information/studies on cancer, olive oil consumption right here.

The conclusions in scientific studies are even more reliable when they are also found in cohort studies, multivariate analyzes (studies where adjustments were made for multiple confounding factors) and high-quality studies.
 

Objectives:
Does postoperative coffee or caffeine consumption causally reduce risk of postoperative ileus (POI) in patients undergoing elective colorectal surgery?

Study design:
This review article included 4 RCTs with 312 subjects.

Results and conclusions:
The investigators found postoperative coffee or caffeine consumption significantly decreased the time to first bowel movement [MD = -10.36 h, 95% CI = -14.61 to -6.11], shortened the length of hospital stay [MD = -0.95 days, 95% CI = -1.57 to -0.34] and was significantly  associated with a 36%-decreased risk of the use of any laxatives after the procedure [RR = 0.64, 95% CI = 0.44 to 0.92].

The investigators found the time to first flatus, time to tolerance of solid food, risk of any postoperative complication, postoperative reinsertion of a nasogastric (NG) tube and anastomotic leakage showed no statistical differences between groups.

The investigators concluded postoperative coffee or caffeine consumption causally improves bowel movement and decreases the duration of hospital stay in patients undergoing elective colorectal surgery. This method is safe and can prevent or treat postoperative ileus (POI).

Original title:
The effect of coffee/caffeine on postoperative ileus following elective colorectal surgery: a meta-analysis of randomized controlled trials by Yang TW, Wang CT, […], Tsai MC.

Link:
https://pubmed.ncbi.nlm.nih.gov/34993568/

Additional information of El Mondo:
Find more information/studies on caffeine and cancer right here.

Postoperative ileus is a prolonged absence of bowel function after surgical procedures, usually abdominal surgery.

Objectives:
Does dietary intake of fiber reduce risk of endometrial cancer?

Study design:
This review article included 16 studies, involving 6,563 cases (persons with endometrial cancer).

Results and conclusions:
The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 14% [RR = 0.86, 95% CI = 0.78 to 0.93].
In stratified analysis, this trend was more pronounced in the case-control studies and in studies conducted in the Americas and Asia.

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 26% after adjusting for education level [RR = 0.74, 95% CI = 0.60 to 0.88].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 30% after adjusting for age [RR = 0.70, 95% CI = 0.57 to 0.83].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 19% in studies with NOS scores of 6 (the higher the NOS scores, the more reliable the studies are) [RR = 0.81, 95% CI = 0.67 to 0.95].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 25% in studies with NOS scores of 7 [RR = 0.75, 95% CI = 0.62 to 0.88].

The investigators concluded dietary fiber intake reduces risk of endometrial cancer. Further efforts should be made to confirm these findings.

Original title:
Association between dietary fiber and endometrial cancer: a meta-analysis by Li H, Mao H, [...], Nan Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31584301

Additional information of El Mondo:
Find more information/studies on fiber, significantly/review article and cancer right here

Objectives:
Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. Therefore, this review article has been conducted.

Do carotenoids (β-cryptoxanthin, α-carotene, β-carotene and lutein and zeaxanthin) reduce risk of bladder cancer?

Study design:
This review article included a total of 22 studies (case-control and cohort studies) involving 516,740 adults.

Results and conclusions:
The investigators found for the highest compared with the lowest category of carotenoid dietary intake a non-significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.76 to 1.03] for bladder cancer.
Non-significantly because RR of 1 was found in the 95% CI of 0.76 to 1.03. RR of 1 means no risk/association.

The investigators found for the highest compared with the lowest category of circulating carotenoid concentrations a non-significantly reduced risk of 64% [RR = 0.36, 95% CI = 0.12 to 1.07] for bladder cancer.

The investigators found for the highest compared with the lowest category of circulating lutein and zeaxanthin concentrations a significantly reduced risk of 47% [RR = 0.53, 95% CI = 0.33 to 0.84] for bladder cancer.
Significantly because RR of 1 was not found in the 95% CI of 0.33 to 0.84. RR of 1 means no risk/association.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 42% [RR = 0.58, 95% CI = 0.36 to 0.94] for every 1 mg increase in daily dietary β-cryptoxanthin intake.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 76% [RR = 0.24, 95% CI = 0.08 to 0.67] for every 1 μmol/L increase in circulating concentration of α-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 27% [RR = 0.73, 95% CI = 0.57 to 0.94] for every 1 μmol/L increase in circulating concentration of β-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 56% [RR = 0.44, 95% CI = 0.28 to 0.67] for every 1 μmol/L increase in circulating concentrations of lutein and zeaxanthin.

The investigators concluded dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene and lutein and zeaxanthin reduce risk of bladder cancer.

Original title:
Carotenoid Intake and Circulating Carotenoids Are Inversely Associated with the Risk of Bladder Cancer: A Dose-Response Meta-analysis by Wu S, Liu Y, […], Ramirez AG.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31800007

Additional information of El Mondo:
Find more information/studies on carotenoid consumption and cancer right here.

 

Objectives:
Is there an association between dietary fat intake and the risk of three major types of skin cancer including basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and cutaneous malignant melanoma (CMM)?

Study design:
This review article included 3 prospective cohort studies (175,675 participants and 30,915 basal cell carcinoma cases, 4,106 squamous cell carcinoma cases and 1,638 cutaneous malignant melanoma cases) and 9 case-control studies (328 basal cell carcinoma cases, 493 squamous cell carcinoma cases, 1,547 cutaneous malignant melanoma cases and 2,660 controls).

Results and conclusions:
The investigators found pooled results indicated that dietary consumption of total fat and saturated fat were not associated with 3 major types of skin cancer.

The investigators found high consumption of monounsaturated fat was significantly associated with a decreased risk of 10% for basal cell carcinoma [RR = 0.90, 95% CI = 0.85 to 0.96]. 

The investigators found high consumption of polyunsaturated fat was significantly associated with an increased risk of 19% for squamous cell carcinoma [RR = 1.19, 95% CI = 1.06 to 1.33]. 

The investigators concluded high consumption of monounsaturated fat decreases risk of basal cell carcinoma while high consumption of polyunsaturated fat increases risk of squamous cell carcinoma. However, these findings should be confirmed by further evidence from well-designed and large-scale prospective cohort studies.

Original title:
Dietary Fat Intake and the Risk of Skin Cancer: A Systematic Review and Meta-Analysis of Observational Studies by Ruan L, Cheng SP and Zhu QX.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31298947

Additional information of El Mondo:
Find more information/studies on fat consumption and cancer right here.
 

Objectives:
The results of epidemiological studies on the relationship between fruit and vegetable intake and lung cancer risk were inconsistent among participants with different smoking status. Therefore, this review article has been conducted.

Do dietary intakes of fruit and vegetables reduce risk of lung cancer?

Study design:
This review article included a total of 12 prospective cohort studies.
The duration of follow-up ranged from 4 to 12.9 years.
No publication bias was found.

Results and conclusions:
The investigators found for dietary consumption of fruit a significantly reduced risk of 14% [summary RR = 0.86, 95% CI = 0.78 to 0.94, I2 = 0.0%, p = 0.642] for lung cancer among current smokers.

Significant means that there is an association with a 95% confidence.

The investigators found for dietary consumption of fruit a significantly reduced risk of 9% [summary RR = 0.91, 95% CI = 0.84 to 0.99, I2 = 0.0%, p = 0.653] for lung cancer among former smokers.
Significant because RR of 1 was not found in the 95% CI of 0.84 to 0.99. RR of 1 means no risk/association.

The investigators found stratified analysis showed that dietary consumption of fruit significantly reduced risk of lung cancer with 23% [RR = 0.77, 95% CI = 0.62 to 0.96] in current smoking subjects from Europe.

The investigators found in linear dose-response analysis that an increase of 100 grams of fruit intake per day was associated with a 5% reduction [RR = 0.95, 95% CI = 0.93 to 0.97, p for trend 0.001] in current smokers.

The investigators found in linear dose-response analysis that an increase of 100 grams of fruit intake per day was associated with a 5% reduction [RR = 0.95, 95% CI = 0.93 to 0.99, p for trend = 0.001] in former smokers.

The investigators found for dietary consumption of vegetables a significantly reduced risk of 13% [summary RR = 0.87, 95% CI = 0.78 to 0.97, I2 = 25.4%, p = 0.226] for lung cancer among current smokers.

The investigators found in linear dose-response analysis that an increase of 100 grams of vegetable intake per day was associated with a 3% lower risk of lung cancer in current smokers [95% CI = 0.96 to 1.00, p for trend = 0.057]. 

The investigators concluded that fruit consumption, at least 100g per day decreases lung cancer risk among current smokers and former smokers, while vegetables consumption, at least 100g per day decreases lung cancer risk of current smokers. These findings may have considerable public health significance for the prevention of lung cancer through dietary interventions.

Original title:
The Associations of Fruit and Vegetable Intake with Lung Cancer Risk in Participants with Different Smoking Status: A Meta-Analysis of Prospective Cohort Studies by Wang C, Yang T, [...], Li D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723574/

Additional information of El Mondo:
Find more information/studies on fruit and vegetables consumption and cancer right here.

 

Objectives:
Findings of epidemiological studies regarding the association between carrot consumption and lung cancer risk remain inconsistent. Therefore, this review article has been conducted.

Do dietary intakes of carrot reduce risk of lung cancer?

Study design:
This review article included a total of 17 case-control studies and 1 prospective cohort study, involving 202,969 individuals and 5,517 patients with lung cancer.

Results and conclusions:
The investigators found in 18 studies a significantly reduced risk of 42% [pooled OR = 0.58, 95% CI = 0.45 to 0.74] for lung cancer by comparing the highest category with the lowest category of carrot consumption.
Exclusion of any single study did not materially alter the pooled OR.

The investigators found based on subgroup analyses for the types of lung cancer a significantly reduced risk of 66% [pooled OR = 0.34, 95% CI = 0.15 to 0.79] for the lung cancer adenocarcinoma by comparing the highest category with the lowest category of carrot consumption.

The investigators found based on subgroup analyses for the types of lung cancer a significantly reduced risk of 39% [OR = 0.61, 95% CI = 0.46 to 0.81] for mixed types of lung cancer by comparing the highest category with the lowest category of carrot consumption.

The investigators concluded that carrot consumption decreases the risk of lung cancer, especially for adenocarcinoma.

Original title:
Is carrot consumption associated with a decreased risk of lung cancer? A meta-analysis of observational studies by Xu H, Jiang H, […], Lu Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31552816

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Find more information/studies on carrot consumption and cancer right here.

 

Objectives:
Observational studies have reported controversial evidence of the association between dietary fat intake and ovarian cancer. Therefore, this review article has been conducted.
Does dietary fat intake increase risk of ovarian cancer among women?

Study design:
This review article included 21 observational studies involved approximately 900,000 women.

Results and conclusions:
The investigators found a significant nonlinear association between dietary total fat intake with the risk of ovarian cancer, with a relatively steep slope at dietary total fat intake higher than 30 g/day [p non-linearity 0.01].

The investigators found, moreover, the risk of ovarian cancer was increased in non-linear form for both saturated and monounsaturated fat from 25 g/day [p non-linearity 0.05].

The investigators found in linear meta-analysis a 2% greater risk of ovarian cancer per 10 g/day increase in total dietary fat intake.

The investigators found in linear meta-analysis a 2% greater risk of ovarian cancer per 0.5 g/day increase in dietary trans fat intake.

The investigators found in linear meta-analysis a 1% greater risk of ovarian cancer per 2.5 g/day increase in dietary monounsaturated fat intake.
However, this association for monounsaturated fat was marginally significant [p = 0.052].

The investigators found in linear meta-analysis a 1% greater risk of ovarian cancer per 50 mg/day increase in dietary cholesterol intake.

The investigators concluded that dietary total, trans, saturated and partially monounsaturated fat as well as cholesterol intake increase risk of ovarian cancer among women.

Original title:
Dietary Fat Intake and Risk of Ovarian Cancer: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies by Sadeghi A, Shab-Bidar S, […], Djafarian K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31058552

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Find more information/studies on fat consumption and cancer right here.
 

Objectives:
Iron has been shown to promote breast carcinogenesis in animal models through generation of oxidative stress and interaction with estrogen. Heme iron, which is found exclusively in animal-sourced foods, is suggested to have a more detrimental effect. Epidemiological evidence of the association between iron and breast cancer risk remains inconclusive and has not been comprehensively summarized. Therefore, this review article has been conducted.

Does dietary iron consumption increase breast cancer risk?

Study design:
This review article included 15 case-control studies and 12 prospective cohort studies.

Of the 17 studies assessing iron intake, 7 were cohort studies with study size ranging from 4,646 to 193,742 participants, follow-up ranging from 5.5 to 20 years and number of breast cancer cases ranging from 188 to 9,305. The remaining 10 studies were case-control studies, of which 4 were hospital-based, 3 were population-based and 3 were nested within existing cohorts, with case numbers ranging from 220 to 3,452.

Of the 11 studies assessing body iron status, 5 were cohort studies with study size ranging from 1,795 to 164,355 participants, follow-up ranging from 7.1 to 17.6 years and number of cases ranging from 80 to 3,238. The remaining 6 studies used a nested case-control or case-cohort design, with follow-up (where reported) ranging from 4 to 15.7 years and case numbers ranging from 107 to 795.

Overall, NOS scores ranged from 4 to 9 (mean = 7.0).

No publication bias was found.

Results and conclusions:
The investigators found compared to lowest category, highest dietary heme iron intake significantly increased risk of breast cancer with 12% [pooled RR = 1.12, 95% CI = 1.04-1.22, I2 = 39%, p heterogeneity = 0.15].

The investigators found each 1 mg/day increase in dietary heme iron intake, was associated with a statistically significant 8% increase in breast cancer risk [pooled RR = 1.08, 95% CI = 1.002–1.17].

The investigators found compared to lowest levels, highest serum iron levels significantly increased risk of breast cancer with 22% [pooled RR = 1.22, 95% CI = 1.01-1.47, I2 = 61%, p heterogeneity = 0.04].

The investigators found serum iron levels exhibited a J-shaped dose-response relationship with breast cancer risk, with strong evidence of a nonlinear effect [p nonlinearity  0.001].

Specifically, a steady increase in risk was noted for serum iron levels above ~ 100 μg/dL, with the association becoming statistically significant at just beyond ~ 125 μg/dL.

The investigators concluded that higher dietary heme iron intake and higher serum iron levels increase breast cancer risk. Further research is needed to better elucidate the association between iron intake/status and risk of breast cancer.

Original title:
Iron intake, body iron status, and risk of breast cancer: a systematic review and meta-analysis by Chang VC, Cotterchio M and Khoo E.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555759/

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Objectives:
Is there an association between poultry and egg consumption and brain cancer risk?

Study design:
This review article included a total of 10 articles (6 articles for poultry consumption and 5 articles for egg consumption).

Results and conclusions:
The investigators found no association between poultry consumption and reduced risk of brain cancer [summarized relative risk = 0.901, 95% CI = 0.703-1.154, I2 = 60.7%, p = 0.018].
No association because RR of 1 was found in the 95% CI of 0.703 to 1.154. RR of 1 means no risk/association.

The investigators found in 4 studies no association between poultry consumption and reduced risk of brain cancer glioma [summarized relative risk = 0.873, 95% CI = 0.737-1.034, I2 = 0.0%, p = 0.838].

The investigators found no association between egg consumption and reduced risk of brain cancer [summarized relative risk = 0.998, 95% CI = 0.552-1.805, I2 = 82.6%, p = 0.001].

The investigators found no association between egg consumption and increased risk of brain cancer glioma [summarized relative risk = 1.472, 95% CI = 0.935-2.316].

The investigators concluded that poultry and egg consumption are not associated with the risk of brain cancer. Due to the limited quality of evidence currently available, more studies related to poultry and egg consumption for brain cancer is necessary.

Original title:
A meta-analysis of the association between poultry and egg consumption and the risk of brain cancer by Luo H, Sun P, [...], Guo Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30782302

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Objectives:
Previous studies had demonstrated some associations between coffee and tea consumption and brain cancer risk resulted in an inconsistent relationship. Therefore, this review article has been conducted.

Does coffee or tea consumption reduce brain cancer risk?

Study design:
This review article included 8 cohort studies and 3 case-control studies, involving 2,583 cases (persons with brain cancer) among 1,684,262 participants.

Based on Egger’s test and funnel plot, there existed no publication bias.

Results and conclusions:
The investigators found highest category of coffee consumption significantly reduced risk of brain cancer with 21.5% [RR = 0.785, 95% CI = 0.580-0.984, I2 = 65.6%, p for heterogeneity = 0.001], when compared with the lowest category.

The investigators found in supgroup analysis highest category of coffee consumption significantly reduced risk of glioma with 24% [RR = 0.760, 95% CI = 0.548-0.972], when compared with the lowest category.

The investigators found in cohort studies highest category of coffee consumption significantly reduced risk of brain cancer with 14.2% [RR = 0.858, 95% CI = 0.700-0.992], when compared with the lowest category. However, this reduced risk was not significant in case-control studies.

The investigators found highest category of coffee consumption significantly reduced risk of brain cancer with 88.3% in Asian populations [RR = 0.217, 95% CI = 0.042-0.896], when compared with the lowest category. However, this reduced risk was not significant in other populations.

The investigators found sensitivity analysis showed pooled RR of coffee consumption ranged from 0.738 [95% CI = 0.542-0.961) to 0.905 [95% CI = 0.754-1.088].

The investigators found highest category of tea consumption significantly reduced risk of brain cancer with 20.2% in American populations [RR = 0.798, 95% CI = 0.646-0.986], when compared with the lowest category.

The investigators found sensitivity analysis showed pooled RR of tea consumption ranged from 0.863 [95% CI = 0.699-1.067] to 0.947 [95% CI = 0.763-1.176].

The investigators found highest category of coffee plus tea consumption significantly reduced risk of brain cancer with 31.6% [RR = 0.684, 95% CI = 0.481-0.975], when compared with the lowest category.

The investigators concluded higher consumption of coffee reduces risk of brain cancer in Asian populations and higher consumption of tea reduces risk of brain cancer in American population. However, future studies with detailed information about sex, lifestyle and some other related factors are warranted to further explore the association between coffee or tea consumption and risk of brain cancer.

Original title:
Association between tea and coffee consumption and brain cancer risk: an updated meta-analysis by Song Y, Wang Z, [....], Guo J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6419842/

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Objectives:
Results from earlier publications on the association of coffee and caffeine and risk of ovarian cancer are inconsistent. Therefore, this review article has been conducted.

Is there an association between coffee and caffeine consumption and risk of ovarian cancer among women?

Study design:
This review article included 22 case-control studies with a total of 40,140 participants, of which 8,568 patients with ovarian cancer. The participants were ≥ 17 years.

Results and conclusions:
The investigators found combining 21 effect sizes from 18 studies, no significant association was observed between total coffee consumption and risk of ovarian cancer [OR = 1.09, 95% CI = 0.94 to 1.26].

The investigators found no significant association between total caffeine intake and ovarian cancer risk [OR = 0.89, 95% CI = 0.55 to 1.45].

The investigators found, in addition, caffeinated coffee intake was not significantly associated with ovarian cancer risk [OR = 1.05, 95% CI = 0.87 to 1.28].

The investigators found, however, combining effect sizes from 5 studies, an inverse significant association between decaffeinated coffee intake and risk of ovarian cancer [OR = 0.72, 95% CI = 0.58 to 0.90].

The investigators concluded decaffeinated coffee consumption could reduce risk of ovarian cancer among women. Could reduce because this review article only included case-control studies and no cohort studies.

Original title:
Coffee and caffeine intake and risk of ovarian cancer: a systematic review and meta-analysis by Shafiei F, Salari-Moghaddam A , […], Esmaillzadeh A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30833443

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Objectives:
Do omega-3 fatty acids in fish consumption reduce risk of breast cancer in Asian patients?

Study design:
This review article included 4 cohort studies and 7 case-control studies with a total of 130,365 Asian patients.

There was not any study with significant publication bias included.

Results and conclusions:
The investigators found omega-3 fatty acids in fish consumption significantly reduced risk of  breast cancer in Asian patients with 20% [OR = 0.80, 95% CI = 0.73-0.87, p 0.00001].
Significant because OR of 1 was not found in the 95% CI of 0.73 to 0.87. OR of 1 means no risk/association.

The investigators concluded omega-3 fatty acids in fish consumption reduce breast cancer risk in Asian patients.

Original title:
Protective Effect of Omega-3 Fatty Acids in Fish Consumption Against Breast Cancer in Asian Patients: A Meta-Analysis by Nindrea RD, Aryandono T, […], Dwiprahasto I.

Link:
http://journal.waocp.org/?sid=Entrez:PubMed&id=pmid:30803190&key=2019.20.2.327

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Fish containing omega-3 fatty acids are salmon, mackerel, herring, lake trout, bluefin tuna, sturgeon, sablefish, anchovy, albacore tuna, whitefish, arctic char, sardines, bluefish, mullet, halibut, striped bass, mahi mahi, pollock, rockfish, rainbow trout, shark, catfish, carp, cod, flounder, grouper, haddock, ocean perch, red snapper, swordfish, pike, sole and tilapia.

Objectives:
Although the relationship between dietary intake and serum levels of trans fatty acids and risk of breast cancer has been investigated extensively, findings are inconsistent. Therefore, this review article has been conducted.

Do dietary intake and serum levels of trans fatty acids increase risk of breast cancer?

Study design:
This review article included 6 cohort studies and 1 nested case-control study on total dietary trans fat intake and 1 cohort study and 4 nested case-control studies on serum trans fatty acids.

Participants were apparently healthy aged 26 years or older.

Results and conclusions:
The investigators found no significant relationship between dietary intake of total trans fatty acids and risk of breast cancer [pooled effect size = 1.02, 95% CI = 0.95-1.10, p = 0.403].

The investigators found in 3 effect sizes from 2 cohort studies and 1 nested case-control study, no significant relation between dietary intake of conjugated linoleic acid (CLA) and risk of breast cancer [pooled effect size = 1.05, 95% CI = 0.95-1.17, p = 0.513].

The investigators found based on 5 effect sizes, each additional 1 g/day dietary intake of total trans fats was not significantly associated with risk of breast cancer [RR = 1.00, 95% CI = 0.99-1.01].

The investigators found high serum levels of trans fats were associated with an increased risk of 37% of breast cancer among postmenopausal women [pooled effect size = 1.37, 95% CI = 1.04-1.81, p = 0.02].

The investigators concluded dietary intake of trans fatty acids (also called trans fats) is not associated with risk of breast cancer. However, a significant positive association is seen between serum trans fats and risk of breast cancer in postmenopausal women.

Original title:
Dietary intake and serum levels of trans fatty acids and risk of breast cancer: A systematic review and dose-response meta-analysis of prospective studies by Anjom-Shoae J, Sadeghi O, […], Esmaillzadeh A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30954361

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Objectives:
Epidemiological studies focusing on the association between folate and breast cancer risk reported inconsistent findings. Therefore, this review article has been conducted.

Does dietary folate intake reduce breast cancer risk?

Study design:
This review article included a total of 23 prospective cohort studies involving 41,516 cases (=women with breast cancer) among 1,171,048 individuals.

Results and conclusions:
The investigators found dietary folate intake significantly reduced risk of oestrogen-receptor-negative breast cancer with 12% [pooled risk ratio = 0.88, 95% CI = 0.78-1.00].

The investigators found dietary folate intake significantly reduced risk of oestrogen-receptor-negative/progesterone-receptor-negative breast cancer with 18% [pooled risk ratio = 0.82, 95% CI = 0.68-0.97].

The investigators found an increment of dietary folate intake of 100 μg per day was associated with a deceased risk of oestrogen-receptor-negative breast cancer with 6% [RR = 0.94, 95% CI = 0.88-0.99].

The investigators found an increment of dietary folate intake of 100 μg per day was associated with a deceased risk of oestrogen-receptor-negative/progesterone-receptor-negative breast cancer with 10% [RR = 0.90, 95% CI = 0.85-0.97].

The investigators found high dietary folate intake significantly reduced breast cancer risk in premenopausal women with 6% [RR = 0.94, 95% CI = 0.88-1.00].

The investigators found high dietary folate intake significantly reduced breast cancer risk in women with moderate or high levels of alcohol consumption with 18% [RR = 0.82, 95% CI = 0.72-0.94].

The investigators concluded that at least 100 μg per day dietary folate intake, reduce both oestrogen-receptor-negative and oestrogen-receptor-negative/progesterone-receptor-negative breast cancer, particularly among premenopausal women and women with moderate or high levels of alcohol consumption.

Original title:
Folate intake and the risk of breast cancer: an up-to-date meta-analysis of prospective studies by Zeng J, Wang K, [...], Chang H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30647438

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Objectives:
Low fruit and vegetable intakes are recognized risk factors for noncommunicable diseases. Therefore, this review article has been conducted.

Do fruit or vegetables intakes reduce noncommunicable diseases, likes cancer, coronary heart disease and all-cause mortality?

Study design:
This review article included 64 reports investigating 98 risk-disease pairs. 56 pairs from 39 reports were assessed as statistically significant, involving 29 burden of diseases.

Results and conclusions:
The investigators found in linear dose analysis for each 100 g/day increase in fruit intakes a significantly reduced risk of 44% [RR = 0.56, 95% CI = 0.42 to 0.74] for esophageal cancer.
Significant means that there is an association with a 95% confidence.

The investigators found in linear dose analysis for each 100 g/day increase in fruit intakes a significantly reduced risk of 28% [RR = 0.72, 95% CI = 0.59 to 0.87] for mouth, pharynx and larynx cancer.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in fruit intakes a significantly reduced risk of 14% [RR = 0.86, 95% CI = 0.84 to 0.88] for stroke.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in fruit intakes a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.88 to 0.90] for all-cause mortality.

The investigators found in linear dose analysis for each 100 g/day increase in vegetable intakes a significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.80 to 0.95] for renal cell cancer.

The investigators found in linear dose analysis for each 100 g/day increase in vegetable intakes a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.84 to 0.95] for non-Hodgkin lymphoma.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in vegetable intakes a significantly reduced risk of 14% [RR = 0.86, 95% CI = 0.84 to 0.89] for coronary heart disease.

The investigators found in nonlinear dose analysis for the first 100 g/day increase in vegetable intakes a significantly reduced risk of 13% [RR = 0.87, 95% CI = 0.84 to 0.90] for all-cause mortality.

The investigators found in nonlinear dose analysis clear increases in protective associations were observed with the first 200 g/day of fruit or vegetable intakes, whereas little further increase or even decrease in protective associations were reported beyond 300 g/day intakes.

The investigators found canned fruit intakes were positively associated with all-cause and cardiovascular disease mortality.

The investigators found pickled vegetable intakes were positively associated with stomach cancer.

The investigators concluded that 100-300 g/day of fruit or vegetables intakes reduce certain cancers, coronary heart disease and all-cause mortality. These findings support existing recommendations for fruit and vegetable intakes. Current comparative risk assessments might significantly underestimate the protective associations of fruit and vegetable intakes.

Original title:
The Associations of Fruit and Vegetable Intakes with Burden of Diseases: A Systematic Review of Meta-Analyses by Yip CSC, Chan W and Fielding R.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30639206

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